Jaundice in Infants and Children

431

ULTRASOUND CLINICS

Ultrasound Clin 1 (2006) 431–441 Jaundice in Infants and Children

Marilyn J. Siegel, MD

- Sonographic examination Spontaneous perforation of the - Overview of cholestatic diseases extrahepatic bile ducts - Neonatal jaundice Inspissated bile syndrome Biliary atresia - Jaundice in older infants and children Neonatal hepatitis syndrome Caroli disease Additional imaging studies to Byler disease differentiate atresia and hepatitis Hepatocellular diseases Alagille syndrome Inﬂammatory diseases of the biliary ducts Choledochal cyst Biliary tract obstruction - References

Real-time sonography remains the screening echogenicity of the normal liver is low to medium study of choice for the evaluation of jaundice in and homogeneous, and the central portal venous infants and children and it is an important tool in vasculature is easily seen (Fig. 1). In the neonate differentiating between obstructive and nonob- and young infant, the hepatic parenchyma and re- structive causes of jaundice [1,2]. The causes of nal cortex are equally echogenic. In individuals 6 cholestasis are multiple, but the three major causes months of age and older, the liver usually is more are hepatitis, biliary atresia, and choledochal cyst. echogenic than the kidney. The patency and flow Other causes include neoplastic processes, cirrhosis, direction of the hepatic vessels should be do- and strictures. cumented with pulsed and color Doppler interroga- This article reviews the common congenital and tion. The liver and adjacent area should also be acquired causes of jaundice in the pediatric patient evaluated for evidence of end-stage liver disease, in- and describes the sonographic findings associated cluding collateral channels (varices), hepatofugal with these conditions. The role of correlative imag- flow, and ascites. ing studies is also reviewed. The diameter of the common duct should be measured on the sagittal scan to confirm the presence or absence of ductal dilatation. The upper Sonographic examination limits of the common duct should not exceed 1 The sonographic examination of infants and chil- mm in neonates, 2 mm in infants up to 1 year of dren who have jaundice includes a detailed exami- age, 4 mm in children 1 to 10 years of age, and 6 nation of the liver, bile ducts, gallbladder, and mm in adolescents and young adults [3]. The distal pancreas. Hepatic size and echotexture should be portion of the common duct is typically larger than thoroughly assessed. The right hepatic lobe should the proximal portion. Ductal size may increase by extend to or just below the right costal margin 1 mm or more during deep inspiration and the in a patient without hyperinflated lungs. The Valsalva maneuver [4]. The cystic duct in children

Radiology and Pediatrics, Mallinckrodt Institute of Radiology, Washington University School of Medicine, 510 South Kingshighway Boulevard, St. Louis, MO, 63110, USA E-mail address: [email protected]

(1) neonatal and (2) older child and adolescent. In the neonate, biliary atresia, the neonatal hepatitis syndrome, and choledochal cyst are the most common causes of jaundice [7–9]. Other causes include syndromic and nonsyndromic bile duct paucity, inspissated bile syndrome, and spontaneous perforation of the extrahepatic bile duct. In older children, jaundice is most often caused by hepatocellular disease, including hepatitis and cirrhosis. Biliary tract obstruction is a less common cause of childhood jaundice. The possible causes of obstructive jaundice include choledochal cyst, cholangitis, stricture, stones, and neoplasms. The results of various laboratory tests of liver function, in conjunction with the pertinent histori- Fig. 1. Normal liver. Transverse sonogram shows ho- cal and physical findings, generally suffice to differ- mogeneous hepatic parenchyma. The echogenic por- entiate between obstructive and nonobstructive tal venous vasculature (arrows) is easily seen. The causes of jaundice. Imaging examinations are used gallbladder (GB) is distended and the wall is thin to confirm the clinical impression. In patients and hyperechoic. PV, portal vein. who have obstructive jaundice, these studies may also often show the level and cause of obstruction. Sonography is the preliminary imaging proce- is not routinely seen unless it is dilated, and then dure. If the extrahepatic ducts are well visualized usually only the distal part of the duct near its inser- by sonography and are normal in caliber and there tion into the common bile duct is seen. is no evidence of intraductal dilatation, further ra- Gallbladder size usually can be assessed subjec- diologic evaluation is rarely needed. Sonography tively, but measurements may be helpful in equivo- is supplemented by radionuclide studies using hep- cal cases. The normal gallbladder length is 1.5 to atobiliary agents (99mTc-IDA analogs) when func- 3.0 cm in neonates and young infants (younger than tional information is needed. Hepatobiliary 1 year old) and the width is approximately 1 cm. In scintigraphy currently is used primarily to confirm older children and adolescents, gallbladder length is suspected diagnoses of choledochal cysts, biliary 3 to 8 cm and width is less than 3.5 cm. The wall of atresia, and neonatal hepatitis. CT or MR imaging the gallbladder should be thin, hyperechoic, and are reserved for cases in which more anatomic de- well defined. The upper limits of wall thickness in tail is needed for surgical planning or the level the fasting state are 3 mm [5]. or cause of obstruction cannot be determined by Feeding of a fatty meal may be helpful in patients sonography [10–15]. who have enlarged gallbladders to assess cystic duct patency. In healthy individuals, maximum empty- ing of the gallbladder occurs between 45 and 60 Neonatal jaundice minutes after the fatty meal, and the mean volume Biliary atresia decreases approximately 60%. Contraction of the Biliary atresia is a rare disease with an incidence of 1 gallbladder after a fatty meal supports the diagnosis in 8,000 to 10,000 live births. It is, however, the sin- of a patent cystic duct. gle most common cause of neonatal cholestasis, ac- Pancreatic size, echotexture, and ductal size should counting for nearly 90% of the surgical causes and be evaluated. Pancreatic size increases with increas- for approximately 40% of all causes of cholestasis ing age of the child [6]. The mean cross-sectional di- [16]. The cause is unclear, but it is believed to be ameter of the pancreatic head ranges between 1 and caused by in utero inflammation that results in fail- 2 cm, the body between 0.6 and 1.1 cm, and the tail ure of the remodeling process at the hepatic hilum between 1 and 2 cm. The normal pancreas is iso- [7]. Histologically, it is characterized by absence of echoic or minimally hyperechoic compared with the extrahepatic bile ducts, proliferation of the the liver. The cross-sectional diameter of the pancre- small intrahepatic bile ducts, periportal fibrosis, atic duct should not exceed 1 to 2 mm. and occasionally multinucleated giant cells. There is a spectrum of changes, depending on the extent of the obliterative process. Complete atresia is pres- Overview of cholestatic diseases ent in 75% to 85% of cases. In the remaining cases, Causes of cholestasis vary with patient age. For this there may be patency of the gallbladder and cystic review, diseases are classified into two main classes: duct or patency of only the gallbladder. Associated Jaundice in Infants & Children 433 anomalies are common (10%–20% of patients) and include choledochal cyst, polysplenia, pre-duo- denal portal vein, azygous continuation of the infe- rior vena cava, diaphragmatic hernia, situs inversus, and hydronephrosis [16–18]. Patients who have biliary atresia and neonatal hepatitis usually present at 1 to 4 weeks of age with jaundice. Distinguishing between neonatal hepatitis and biliary atresia is important, because biliary atresia requires early surgical intervention to prevent biliary cirrhosis, whereas neonatal hepatitis is managed medically. Surgical treatment varies with the level of obstruction [7,8]. When there is extrahepatic biliary obstruction (15%– 25% of cases), a direct anastomosis between the patent portion of the extrahepatic bile duct and intestine is performed. When there is intrahepatic Fig. 2. Biliary atresia, cord sign. Transverse sonogram biliary atresia, a Kasai hepatoportoenterostomy through the porta hepatis shows an echogenic cord (anastomosis of a segment of small bowel to the (arrowheads) anterior to the portal vein (arrow), indi- portal region) is performed [7,8,19]. The success cating fibrosis along the course of the common he- rate of the Kasai procedure is inversely propor- patic duct. tional to patient age. Bile flow can be re-estab- lished in up to 90% of infants who are younger Neonatal hepatitis syndrome than 2 months of age at the time of hepatoportoenterostomy and in approximately 50% in those The neonatal hepatitis syndrome is the term given who are 2 to 3 months. The success rate decreases to nonspecific hepatic inflammation that develops to less than 20% when surgery is performed after secondary to several different causes, including in- 90 days of age because of the presence of cirrhosis fection (cytomegalovirus, herpes simplex, toxoplas- [7–9]. Liver transplantation is often required in mosis, protozoa, syphilis), metabolic defects (alpha older infants and children who have intrahepatic 1-antitrypsin deficiency, galactosemia, glycogen biliary atresia. storage disease, tyrosinosis), and Alagille syndrome. A spectrum of findings may be seen sonographically, reflecting the underlying histology. The liver size and parenchymal echogenicity may be normal or increased [1]. The intrahepatic ducts are typically not dilated. The extrahepatic duct is typically not visualized. A remnant of the extrahepatic duct, however, may be noted in the porta hepatis [20– 23]. This remnant appears as a triangular or tubular echogenic structure just superior to the portal vein bifurcation. This finding has been termed the triangular cord sign and correlates with fibrous tissue in the porta hepatis at histologic examination (Fig. 2). The sign is reliable for the diagnosis of extrahepatic biliary atresia and has a specificity approaching 100% and a sensitivity of approximately 85%. In biliary atresia, the gallbladder is usually small or absent (Fig. 3), although a normal-sized gallbladder may be seen when the atresia is distal to the insertion of the cystic duct (approximately 10% of cases). The finding of a small gallbladder (<1.5 cm in diameter) is nonspecific and may be seen with biliary atresia or neonatal hepatitis. Con- tractility and changes in gallbladder size after a milk Fig. 3. Biliary atresia. Transverse scan shows normal feeding are rare in patients who have biliary atresia parenchymal echogenicity. The gallbladder (arrow) (<10% of cases) [24,25]. is small. The common bile duct was not visualized. 434 Siegel

Additional imaging studies to differentiate atresia and hepatitis Hepatobiliary scintigraphy Because the sonographic findings of biliary atresia and hepatitis overlap, hepatobiliary scintigraphy is usually performed to assess the presence or absence of bile excretion into the bowel. Infants who have biliary atresia less than 3 months of age usually show normal hepatic extraction of tracer but no excretion of the radionuclide into the small intestine (Fig. 5A), whereas infants older than 3 months of age show decreased extraction of tracer and no excretion into the bowel. In neonates who have neonatal hepatitis, parenchymal extraction is Fig. 4. Neonatal hepatitis. Longitudinal sonogram diminished but there is some excretion into the shows diffusely increased and coarsened echogenicity. bowel (Fig. 5B). The gallbladder is small and filled with sludge (arrow). The sensitivity and specificity of scintigraphy for the diagnosis of biliary atresia in infants less than 3 months of age is approximately 95% and 80%, re- Histologic examination shows multinucleated giant spectively. The presence of small bowel activity ex- cells with hepatic parenchymal disruption and little cludes biliary atresia as the cause of jaundice. bile within the bile duct canaliculi. Similar to bili- Differentiation between biliary atresia and neonatal ary atresia, the cause is believed to be an in utero in- hepatis is more difficult when there is poor hepato- flammatory process and the disease process usually cellular function. manifests with jaundice at 3 to 4 weeks of life. At sonography, the liver size and echogenicity may be normal or increased, and the biliary ducts are not dilated [1,2] (Fig. 4). The gallbladder may Magnetic resonance imaging be small, normal, or increased in size. Changes in MR cholangiopancreatography may also be useful gallbladder size after a milk feeding can occur in pain assessing the patency of intra- and extrahepatic tients who have neonatal hepatitis, reflecting pa- biliary ducts [10,12]. Complete visualization of tency of the common hepatic and common bile the extrahepatic biliary system excludes biliary atre- duct [24]. sia as the cause of cholestasis [10].

Fig. 5. Hepatobiliary imaging in neonatal jaundice. (A) Biliary atresia. Hepatobiliary scan obtained 6 hours after injection of Tc-99m disofenin demonstrates hepatic uptake but absence of excretion into the central bile ducts and intestine. (B) Neonatal hepatitis. Hepatobiliary scan obtained 3 hours after injection shows radioactivity in the gallbladder (*) and within bowel (arrows). On more delayed images, there was poor clearance of radioactivity from the liver. Jaundice in Infants & Children 435

Cholangiography multiple intrahepatic biliary cysts and is considered Cholangiography is performed when other clinical to be a separate disorder (see later discussion). or imaging findings suggest the diagnosis of biliary Choledochal cysts in neonates and young infants atresia. It may be performed percutaneously, endo- may coexist with biliary atresia [17,18]. scopically, or intraoperatively. Contrast medium is At sonography, the choledochal cyst appears as injected into the gallbladder. a fluid-filled cystic mass in the region of the porta hepatis that is separate from the gallbladder (Fig. 6). Intrahepatic biliary duct dilatation is pres- Alagille syndrome ent in approximately half of affected patients and Alagille syndrome (also known as arteriohepatic typically is limited to the central portions of the left dysplasia) is a hereditary disorder, usually an auto- and right main hepatic ducts. Generalized ductal di- somal dominant trait with variable penetrance latation, typical of acquired obstruction, is absent. [8,26]. A deletion in the short arm of chromosome The cysts tend to be smaller and ductal dilatation 20 has been seen in some patients [26]. It is associ- is absent when there is concomitant biliary atresia ated with abnormalities of the liver (cholestatic [17,18]. Complications associated with choledo- jaundice), heart (most commonly peripheral pul- chal cysts include cholelithiasis, choledocholithia- monic stenosis), skeleton (butterfly vertebrae and sis, ascending cholangitis, intrahepatic abscesses, hemivertebrae), eye, kidneys, and abnormal facies biliary cirrhosis, portal hypertension, and hepato- (frontal bossing, deep-set eyes, bulbous tip of the biliary malignancy, usually adenocarcinomas. The nose, and pointed chin). The associated findings risk for malignancy increases with age [27]. help to distinguish Alagille syndrome from biliary When a choledochal cyst is demonstrated sono- atresia. Patients typically present with jaundice in graphically, scintigraphy with hepatobiliary agents the neonatal period. Histologic examination shows is performed to confirm that the cystic mass com- paucity and hypoplasia of the interlobular bile municates with the biliary system. Preoperative CT ducts. Imaging findings are similar to those de- is acquired to further define the anatomy of the in- scribed for neonatal hepatitis. trahepatic biliary tree and the distal common bile duct [13]. MR cholangiography may also be useful in the preoperative anatomic assessment of these Choledochal cyst lesions [10–12]. Choledochal cyst is a congenital dilatation of the common bile duct, with 30% of cases found to occur in the first year of life, 50% between 1 and 10 Spontaneous perforation years of age, and 20% in the second decade or later of the extrahepatic bile ducts [27]. The classic clinical presentation is jaundice, Spontaneous perforation of the extrahepatic bile abdominal pain, and mass, although this triad is ducts is a cause of neonatal jaundice and ascites, present in only 20% to 50% of patients [27]. This usually affecting infants between 1 week and 4 abnormality is believed to be the result of an abnor- months of age. The clinical findings include ascites, mal insertion of the common bile duct into the mild jaundice, failure to thrive, and abdominal dis- pancreatic duct, which allows reflux of pancreatic tension. The serum bilirubin level is elevated, enzymes into the biliary system. This reflux re- whereas other liver function tests are normal. The sults in a chemical cholangitis, which weakens the latter feature is helpful in differentiating perforation walls of the bile duct, eventually leading to ductal from neonatal hepatitis and biliary atresia, which dilatation [28]. have similar clinical findings but abnormal liver Four types of choledochal cysts have been de- function tests. The most frequent site of perforation scribed [29]. The type 1 cyst, accounting for 80% is the junction of the cystic and common bile ducts. to 90% of cases, is subdivided into type 1A, cystic Rarely the perforation involves the common he- dilatation of the common duct; type 1B, focal seg- patic duct, gallbladder, or junction of the cystic duct mental common duct dilatation; and type 1C, fusi- and gallbladder [30]. form dilatation of the common bile duct. The type Sonography shows generalized ascites or a locu- 2 cyst, accounting for approximately 2% of cases, is lated fluid collection in the porta hepatis [30] a true diverticulum arising from the common duct. (Fig. 7). Echogenic debris or fine septations may The type 3 cyst, accounting for 1% to 5% of cases, is be present within the ascitic fluid. The biliary tree a choledochocele involving only the intraduodenal is not dilated because it is not obstructed. Gallblad- portion of the duct. The type 4 cyst is subdivided der or distal common duct calculi may be associ- into type 4A, multiple intrahepatic cysts and an ex- ated findings. Hepatobiliary scintigraphy is useful trahepatic cyst, and type 4B, multiple extrahepatic to confirm the diagnosis by showing leaking of ra- cysts. The type 5 cyst, or Caroli disease, consists of dioactive tracer into the peritoneal cavity. Surgical 436 Siegel

Fig. 6. Choledochal cyst in a young boy with jaundice. (A) Longitudinal and (B) transverse sonograms through the liver demonstrate a cystic mass (C), representing the choledochal cyst, in the porta hepatis separate from the gallbladder (GB). P, pancreas. (C) Contrast-enhanced CT scan conﬁrms the cystic mass (C), which is the dilated common bile duct.

placement of a drainage tube in the area of perfora- cyst (see earlier discussion) and Caroli disease, dis- tion usually results in spontaneous closure. eases of the hepatocytes, and inflammatory and obstructive lesions of the biliary ducts. Inspissated bile syndrome The inspissated bile or bile-plug syndrome refers to Caroli disease an extrahepatic obstruction of the bile ducts by bil- Caroli disease, also known as congenital cystic dila- iary sludge [2]. This condition typically affects full- tion of the intrahepatic biliary tract, has two forms. term infants. Inspissated bile syndrome has been One form is characterized by segmental, saccular di- associated with massive hemolysis, hemorrhage, to- lation of the intrahepatic bile ducts, an increased tal parenteral nutrition, cystic fibrosis, and various frequency of calculus formation and cholangitis, intestinal diseases (Hirschsprung disease, intestinal and the absence of cirrhosis and portal hyperten- atresias, and stenoses). Sonography shows moder- sion. The other form is characterized by hepatic fi- ately or highly echogenic bile within the gallblad- brosis, cirrhosis, and portal hypertension. Both der and often within dilated intra- or extrahepatic forms of Caroli disease are associated with renal bile ducts. Although the bile is echogenic, it does cystic disease, including renal tubular ectasia (med- not cause acoustic shadowing. The ductal dilatation ullary sponge kidney), cortical cysts, and autosomal may be difficult to recognize if the echogenicity of recessive polycystic disease. Patients who have Car- the inspissated bile and liver are similar [1,2]. oli disease, like those who have choledochal cysts, have an increased risk for developing cholangiocar- cinoma. Patients may present in the neonatal pe- Jaundice in older infants and children riod [31], but the vast majority present as young The causes of jaundice in older children and adoles- adults who have abdominal pain, fever, and jaun- cents include cystic diseases, including choledochal dice or with portal hypertension. Jaundice in Infants & Children 437

Fig. 7. Spontaneous perforation of the common bile duct. (A) Transverse sonogram through the upper abdomen demonstrates ascites (A) in the perihepatic space. (B) On a more caudad image, a loculated ﬂuid (F) collection and a calculus (arrow) are noted in the porta hepatis.

Sonography shows multiple dilated tubular Byler disease structures, typical of biliary radicals (Fig. 8). These Byler syndrome (also known as progressive familial can converge, creating larger saccular areas [31]. intrahepatic fibrosis) is a familial intrahepatic cho- The portal radicals may be partially or completely lestatic syndrome that is associated with cystic he- surrounded by the dilated ducts (termed the central patic lesions and jaundice. Histologically, there is dot sign) [32] (Fig. 9). The extrahepatic bile ducts periportal fibrosis, micronodular cirrhosis, and can be normal, narrowed, or associated with a chol- periductal cysts. Symptoms, including jaundice, edochal cyst. Findings of portal hypertension may pruritus, and hepatomegaly, usually appear by the be observed in patients who have hepatic fibrosis. end of the first year of life. The sonographic findings

Fig. 8. Caroli disease. (A) Transverse Doppler sonogram shows dilatation of the intrahepatic bile ducts (arrows), which converge toward the porta hepatis. The color Doppler image helps confirm the absence of flow in the dilated ducts. Flow is seen in the portal vein (PV). (B) CT confirms saccular dilatation of the bile ducts. (From Siegel MJ. Gallbladder and biliary tract. In: Siegel MJ, editor. Pediatric sonography. 3rd edition. Philadelphia: Lippincott Williams & Wilkins; 2002. p. 276–304; with permission). 438 Siegel

Fig. 9. Caroli disease. Transverse sonogram shows dilated ducts (arrows) that completely envelope the Fig. 10. Acute hepatitis. Starry sky liver. Sagittal sono- portal radicals. This appearance is termed the central gram of the liver shows brightly echogenic portal ve- dot sign. nous triads. The liver was also moderately enlarged.

are multiple saccular cystic lesions, some of which Inflammatory diseases of the biliary ducts may contain echogenic portal veins (the central Sclerosing cholangitis dot sign) [33]. Unlike Caroli disease, the cysts in By- Sclerosing cholangitis is a chronic cholestatic disor- ler disease do not communicate with the bile ducts. der characterized by inflammatory obliterative fibrosis of the extrahepatic and intrahepatic bile ducts leading to biliary cirrhosis and ultimately Hepatocellular diseases liver failure [34]. This entity has been associated with chronic inflammatory bowel disease, Langer- Hepatocellular disease can be classified into two hans histiocytosis X, and immunodeficiency disor- major classes: infectious (acute and chronic hepati- ders [34]. Histologic examination shows multiple tis) and noninfectious (metabolic disorders, drugs, segmental strictures, diverticula formation between toxins, and autoimmune diseases). The sono- areas of stricture, and mural thickening of the bile graphic appearance of the liver depends on the se- ducts. Clinical manifestations include jaundice verity of the insult, rather than on the causative and right upper quadrant pain. Most affected pa- agent [1]. Sonography is usually normal in cases tients are adolescents or adults. of mild acute infectious hepatitis. Sonographic findings in severe acute hepatitis include hepatomegaly, decreased parenchymal echogenicity, and increased echogenicity of the portal venule walls (starry sky liver) (Fig. 10). The gallbladder wall may be small, thick-walled, and filled with intralu- minal sludge. In chronic active hepatitis, the liver often appears heterogeneous and hyperechoic with irregular margins and decreased visualization of the portal venous radicles (Fig. 11). The gallbladder may be small and contain thick bile, sludge, or stones, and collateral vessel formation may be noted. Metabolic causes of jaundice include Wilson disease, cystic fibrosis, glycogen storage disease, tyrosinemia, and a1-antitrypsin deficiency. The sonographic appearance of these disorders is nonspecific and can be similar to that of acute or chronic hepatitis. A definitive diagnosis requires correlation with clinical information and labora- Fig. 11. Chronic hepatitis. Longitudinal sonogram of tory results, and in many cases biopsy is needed the liver shows an enlarged liver with irregular mar- to confirm the diagnosis. gins and diffusely coarse echotexture. Jaundice in Infants & Children 439

extrahepatic bile ducts, and a dilated, thick-walled gallbladder wall [35–37]. An additional ﬁnding is a hyperechoic nodule in the distal end of the common bile duct caused by edema of the papilla of Vater [38].

Biliary tract obstruction Sonographic features Biliary obstruction resulting in jaundice is usually the result of stone disease. Acute pancreatitis, neoplasm, and benign strictures are less common causes of obstructive jaundice in children. The sonographic diagnosis of biliary obstruction is based Fig. 12. Sclerosing cholangitis. Longitudinal sono- on the demonstration of dilated intrahepatic or ex- gram shows a dilated, thick-walled common bile duct trahepatic bile ducts. Dilated intrahepatic biliary (arrows) (diameter, 9 mm). PV, portal vein; SV, splenic radicles appear as multiple, anechoic branching vein. structures that enlarge as they approach the porta hepatis. The dilated common hepatic and common bile ducts may appear as round or tubular anechoic Sonographic findings include a thick-walled gall- structures near the porta hepatis or the head of the bladder, thick-walled dilated intrahepatic ducts pancreas (Fig. 13). (Fig. 12), intrahepatic and intraductal stones, cholelithiasis, and segmental ductal narrowing Cholelithiasis and choledocholithiasis secondary to stricturing. The strictures may be diffi- Stones in the common bile duct usually originate in cult to detect sonographically unless the ducts are the gallbladder and migrate distally. Cholelithiasis dilated. In longstanding disease, sonography may in neonates has been associated with congenital show findings of biliary cirrhosis and portal anomalies of the biliary tract, total parenteral nutri- hypertension. tion, furosemide therapy, phototherapy, dehydra- tion, infection, hemolytic anemias, and short-gut AIDS-related cholangitis syndrome [9]. In older children, causes of choleli- The common biliary tract abnormalities in children thiasis include sickle cell disease, cystic fibrosis, who have AIDS are acalculous cholecystitis and malabsorption, total parenteral nutrition, liver dis- cholangitis. The sonographic findings in AIDS- ease, Crohn disease, bowel resection, and hemolytic related cholangitis are similar to those of sclerosing anemia. cholangitis and include ductal dilatation and wall Choledocholithiasis typically manifests as irregularity (Fig. 13), stricture of the intra- and brightly echogenic shadowing foci within the

Fig. 14. Choledocholithiasis. Longitudinal scan at the Fig. 13. AIDS-related cholangitis. Longitudinal sono- level of the pancreatic head (P) shows a stone gram at the level of the porta hepatitis demonstrates (between calipers) without shadowing. At operation, intrahepatic ductal dilatation (arrows). (Courtesy of calcium bilirubinate stones were found in the gall- Edward Lee, MD, Boston, MA). bladder and distal duct. Ductal diameter is 11 mm. 440 Siegel

Fig. 15. Cystic duct stone. (A) Longitudinal scan shows a calculus (calipers) in the cystic duct. A second calculus (arrow) is noted in the distal common bile duct, which is dilated. (B) Endoscopic retrograde cholangiogram con- ﬁrms the stone (arrow) in the cystic duct. (From Siegel MJ. Gallbladder and biliary tract. In: Siegel MJ, editor. Pediatric sonography. 3rd edition. Philadelphia: Lippincott Williams & Wilkins; 2002. p. 276–304; with permission).

biliary ducts and is usually associated with ductal in patients who have biliary obstruction in whom dilatation (Fig. 14). The calculi obstruct anywhere no calculus or other obstructing lesion can be visu- in the biliary duct, but most cause obstruction at alized. An abrupt transition from a dilated duct to the level of the pancreatic head. The sensitivity for one of normal caliber is a finding suggestive of detection of choledocholithiasis is lower for stones stricture. in the distal versus the proximal duct. A calculus impacted in the distal duct can be more difficult to detect because of adjacent or overlying bowel gas and References because the calculus is surrounded by the echogenic pancreatic head. [1] Gubernick JA, Rosenberg HK, Ilaslan H, et al. US approach to jaundice in infants and children. Ra- Cystic duct stones diographics 2000;20:173–95. Mirizzi syndrome is a rare cause of biliary obstruc- [2] Siegel MJ. Gallbladder and biliary tract. In: tion in children. It is secondary to an impacted cys- Siegel MJ, editor. Pediatric sonography. 3rd edi- tic duct stone, which causes extrinsic compression tion. Philadelphia: Lippincott Williams & Wil- or inflammatory stricture of the common duct. kins; 2002. p. 276–304. Sonographic findings include calculi in the gall- [3] Hernanz-Schulman M, Ambrosino MM, Freeman PC, et al. Common bile duct in chil- bladder neck or in the cystic duct and dilated intra- dren: sonographic dimensions. Radiology 1982; hepatic ducts, including the common hepatic duct 145:437. (Fig. 15). [4] Wachsberg RH. Respiratory variation of extrahepatic bile duct diameter during ultrasonography. Biliary neoplasms J Ultrasound Med 1994;13:617. Rhabdomyosarcoma of the biliary tract is rare, but [5] Wolson AH. Ultrasound measurements of the it is the most common neoplasm of the biliary tract gallbladder. In: Goldberg BB, Kurtz AB, editors. in children. Most rhabdomyosarcomas arise in the Atlas of ultrasound measurements. Chicago: Year porta hepatis and involve the cystic duct. Sono- Book Publishers, Inc.; 1990. p. 108–12. graphic findings are intra- and extrahepatic ductal [6] Siegel MJ, Martin KW, Worthington JL. Normal dilatation and an echogenic mass without acoustic and abnormal pancreas in children: US studies. shadowing. Rhabdomyosarcoma spreads by direct Radiology 1987;165:15–8. [7] Balistreri WF, Grand R, Hoofnagle JH, et al. Bili- extension to contiguous structures or by hematoge- ary atresia: current concepts and research direc- nous or lymphatic dissemination to lymph nodes, tions. Summary of a symposium. Hepatology lungs, bone, bone marrow, or liver. 1996;23:1682–90. [8] Balistreri WF, Schubert WK. Liver diseases in Biliary duct strictures infancy and childhood. In: Schiff L, Schiff ER, Biliary stricture is an uncommon cause of distal ob- editors. Diseases of the liver. 7th edition. struction, but the diagnosis needs to be considered Philadelphia: JB Lippincott; 1993. p. 1099–203. Jaundice in Infants & Children 441

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